Yes, it's perfectly correct. Would it help you understand it if you inserted the words 'which is' before the adjective 'independent'?
Society .. has no reality which is independent of the individuals that make it up.
This means that the only reality which society has is that of the individuals which make up the society. Or, in other words, society only exists in terms of the people who form it. You can't separate 'society' from the people in it, because the society wouldn't exist without these individuals.